London - A good diet, exercise and cutting back on booze all come highly recommended, but scientists have identified another possible strategy for preventing obesity: head for the hills.
Research in Spain has found that people who live at high altitudes are 13 percent less likely to become overweight or obese.
Experts believe the phenomenon may result from the body's natural response to low-oxygen environments, suppressing hunger and enabling us to obtain energy from less oxygen, and less food.
The study, which was presented at the European Congress on Obesity in Prague recently, recruited 9,300 students of healthy weight, living throughout Spain.
They were followed up for an average of eight and a half years and their postcodes divided into three categories: low altitude (below 124m above sea level), medium (124m - 456m) and high (above 456m).
More than 2 000 of the study participants went on to become overweight, but those living above 456m were 13 percent less likely to do so than those who lived below 124m.
The results were adjusted for factors such as diet, age and rates of activity - so cannot be explained by the extra exercise people living up hills might be getting.
Instead, researchers from the University of Navarra said that the results were likely to be linked to low oxygen intake, or hypoxia, which causes increased production of leptin and other hormones involved in appetite control.
A previous study in America, which looked at greater extremes of altitude, found that those who lived in towns and cities below 500m above sea level, were five times more likely to be obese than their countrymen living in the mountains, 3 000m or more above sea level.
The Independent